Ported upper bout....?

[fitness1]

Wow - those ports are HUGE relative to the body size/depth - I know they are adjustable, but holy cow!!!

I wish you could play my Solista - tiny little ports that make an incredible difference in basically every element of the tonal picture. They are actually slightly larger and more beveled than in this picture now, but only about 10% larger tops.

[stringjunky]

Originally Posted by fitness1

Wow - those ports are HUGE relative to the body size/depth - I know they are adjustable, but holy cow!!!

I wish you could play my Solista - tiny little ports that make an incredible difference in basically every element of the tonal picture. They are actually slightly larger and more beveled than in this picture now, but only about 10% larger tops.

How big are the actual holes?

[fitness1]

Originally Posted by stringjunky

How big are the actual holes?

Internal diameter is 7/16

[stringjunky]

Originally Posted by fitness1

Internal diameter is 7/16

Are you sure? That's tiny. Just looked on a ruler.

[Howard Emerson]

Originally Posted by stringjunky

Are you sure? That's tiny. Just looked on a ruler.

Yeah, it sounds wrong, but given the visual cues of the side of a classical guitar being 4”+ and that there’s 2 holes there...I’d say they’re less than a half inch each.

HE

[fitness1]

Originally Posted by stringjunky

Are you sure? That's tiny. Just looked on a ruler.

Yes - completely sure.

I also had a Cordoba C9 I put dual ports in and they were single/larger. I tried to duplicate the total area to make it the same.

[stringjunky]

Originally Posted by fitness1

Yes - completely sure.

I also had a Cordoba C9 I put dual ports in and they were single/larger. I tried to duplicate the total area to make it the same.

Thanks Fitness. I suppose I need to think about the effect of the total area of the holes together and not individually. Is the effect as loud as a single hole of equivalent area?

[fitness1]

Originally Posted by stringjunky

Thanks Fitness. I suppose I need to think about the effect of the total area of the holes together and not individually. Is the effect as loud as a single hole of equivalent area?

Very hard to tell - the tonal characteristics of the two guitars were quite different. The Mahogany C9 had a smoothness to the tone and the Solista has a little more string separation and boldness to it.

I was surprised when I preferred the Solista as I'd had the C9 for almost 3 years and nothing else had come close.

[TomB'sox]

Originally Posted by Howard Emerson

Tom,
Tim placed the mic 6” from the instruments, right?

I have no doubt there was a different reading between ports open and closed on the machine. In that regard Tim is correct.

My audience is at least 6’ away.

Don’t let the strength of my convictions dissuade you in any way, and I’m serious about that. I’m just very pragmatic.

Best,
Howard Emerson

Just to be clear about this, he started at 6 inches, but if you read all the way through, he also did 6 feet, 10 feet and 20 feet with higher numbers noted at all distances with the port open.

I am not saying they were statistically significant, but they were all higher at all distances with the port open.

Thanks for the intelligent and respectful discourse. The AGF benefits from this type of interaction

Tom

[Tim McKnight]

Originally Posted by stringjunky

For a standard-size soundhole, what would be your upper limit size for a round port on the upper bout, Tim?

Hi Stringjunky, With a standard (factory installed) main sound hole, I would not exceed 1" in total diameter for a side port.

I started experimenting with side sound ports in the early 1990's after seeing a picture of side sound port on a mid 18th century classical guitar. The photo was in a book I borrowed from a library and that guitar resides in a museum but I can't remember exactly where the museum is but I think its in EU. The photo intrigued me so I got out my Dremel and cut my first sound port in my Martin kit guitar, which was my main test mule at the time. My kids ran into the house and told mom to call the "white coats" because dad cut a hole in his beloved Martin.

Thanks Tom for pointing out that my testing was done from different distances and also measured 360* around the player. My testing was many many moons ago and my memory isn't as keen as it used to be. The test, as Tom pointed out, isn't totally definitive but the limited data clearly suggests the benefits of ports are certainly measurable. I had hoped that someone would pick up the ball and continue the study but I've not read of any further tests or papers since. My tests were limited because I had borrowed the decibel meter and only had it for 24 hours which didn't provide enough time to do the amount of tests I would have liked.

A few years later, we exhibited guitars beginning in the late 1990's at the Healdsburg Guitar Show. There was only one other luthier which I saw there exhibiting with a side sound port but I don't recall who it was. The next show, 3 or 4 more luthiers exhibited with side sound ports and the proverbial snow ball started to gain momentum. I didn't invent ports nor do I claim to but since they have been around since the 1700's, or possibly earlier, who really cares because the darn things work, to varying degrees and generally enhance the player's experience, which is what most of us are after anyways, right?

I would also mention that ports with smaller and a greater number of holes, openings or shapes, tend to be discernibly louder than just one single hole. Our Luckenbooth port is louder than a single circle or oval. I can't intelligently discuss why multiple holes are louder other than personal experience tells me so. We have also used, spaced apart, dual ports too and they provide an even different listening perspective. Perhaps Fitness1 may be able to chime in as I see him going in the multi-port direction too.

[fitness1]

Originally Posted by Tim McKnight

I would also mention that ports with smaller and a greater number of holes, openings or shapes, tend to be discernibly louder than just one single hole. Our Luckenbooth port is louder than a single circle or oval. I can't intelligently discuss why multiple holes are louder other than personal experience tells me so. We have also used, spaced apart, dual ports too and they provide an even different listening perspective. Perhaps Fitness1 may be able to chime in as I see him going in the multi-port direction too.

My best guess after being an audiophile for many years and having a pretty good set of ears is simply dispersion (as in width/degrees) It's one of the reasons stereo with two speakers sounds much better than Mono with one.

When I first started porting guitars intuition told me that very small holes would have a big impact and not change the overall tone of the guitar, just make it better. It's been correct in every case.

In the case of the dual ports - I think it's simply because there is more air moving in the lower bout than the upper bout, and when you slightly open that up and let it breathe, some pretty substantial things can happen!

[runamuck]

I don't know this from my own experience but have read that, as a general rule and to some extent, reducing the soundhole diameter increases low frequency response.

If that's true, does adding a sound port decrease bass response?
If not, why?

[fitness1]

Originally Posted by runamuck

I don't know this from my own experience but have read that, as a general rule and to some extent, reducing the soundhole diameter increases low frequency response.

If that's true, does adding a sound port decrease bass response?
If not, why?

I believe it does to a certain extent if it's too large

Home audio speakers have been using ports for many years, but you never see them more than about 3" diameter on a huge speaker box. There's a reason for that!

[David Wren]

Originally Posted by Trevor B.

G.W. Barry is building me a 12 fret steel string acoustic guitar this coming build season. He offers a side port option. I played one of his guitars without a side port and another with a side port. Both guitars sounded great but I could hear the one with the side port much better, so I'm going with that option.

Hey Trevor ... G.W. Barry is one of my very favorite builders anywhere, any time ... you'll love your new guitar I'm sure!

And for the record ... I love side ports (generally speaking) and for some reason, get my best results from un-segmented ones (i.e. one hole versus multiple holes making a decorative motif.

[stringjunky]

Originally Posted by Tim McKnight

Hi Stringjunky, With a standard (factory installed) main sound hole, I would not exceed 1" in total diameter for a side port.

I started experimenting with side sound ports in the early 1990's after seeing a picture of side sound port on a mid 18th century classical guitar. The photo was in a book I borrowed from a library and that guitar resides in a museum but I can't remember exactly where the museum is but I think its in EU. The photo intrigued me so I got out my Dremel and cut my first sound port in my Martin kit guitar, which was my main test mule at the time. My kids ran into the house and told mom to call the "white coats" because dad cut a hole in his beloved Martin.

Thanks Tom for pointing out that my testing was done from different distances and also measured 360* around the player. My testing was many many moons ago and my memory isn't as keen as it used to be. The test, as Tom pointed out, isn't totally definitive but the limited data clearly suggests the benefits of ports are certainly measurable. I had hoped that someone would pick up the ball and continue the study but I've not read of any further tests or papers since. My tests were limited because I had borrowed the decibel meter and only had it for 24 hours which didn't provide enough time to do the amount of tests I would have liked.

A few years later, we exhibited guitars beginning in the late 1990's at the Healdsburg Guitar Show. There was only one other luthier which I saw there exhibiting with a side sound port but I don't recall who it was. The next show, 3 or 4 more luthiers exhibited with side sound ports and the proverbial snow ball started to gain momentum. I didn't invent ports nor do I claim to but since they have been around since the 1700's, or possibly earlier, who really cares because the darn things work, to varying degrees and generally enhance the player's experience, which is what most of us are after anyways, right?

I would also mention that ports with smaller and a greater number of holes, openings or shapes, tend to be discernibly louder than just one single hole. Our Luckenbooth port is louder than a single circle or oval. I can't intelligently discuss why multiple holes are louder other than personal experience tells me so. We have also used, spaced apart, dual ports too and they provide an even different listening perspective. Perhaps Fitness1 may be able to chime in as I see him going in the multi-port direction too.

Thanks Tim.